Saskatchewan Organic On-Farm Research: Part I: Farm Survey and Establishment of On-farm Research Infrastructure

Transcription

1 Saskatchewan Organic On-Farm Research: Part I: Farm Survey and Establishment of On-farm Research Infrastructure 2002 Report March 15, 2003 Principal Investigators: Steve Shirtliffe J. Diane Knight Department of Plant Sciences Department of Soil Science University of Saskatchewan 51 Campus Drive Saskatoon, SK S7N 5A8 1

2 (a) Abstract/ Summary This project was the first part of a two-part study designed to address soil fertility management and weed management priorities in organic agriculture. These priorities were identified by Saskatchewan organic growers through a provincial needs assessment survey, conducted by Saskatchewan Agriculture and Food in the winter of The overall objective of this project was to investigate how agronomic practices used in Saskatchewan organic farming systems affect soil fertility and weed populations. Organic cropping and management practices used by experienced growers were identified and characterized through a written questionnaire aimed at specific fields on their farms. Soil and weed analyses from the same fields were used to assess soil fertility levels and weed management strategies. This information was applied to design replicated experiments which are currently being carried out in the second part of this study. To enable farmer input in this study, an advisory committee has been established with representation from organic growers throughout the province, scientists and government officials. To assist farmers in their efforts to develop a farmer-directed on-farm research network, workshops on planning and conducting on-farm research were held in the northwestern and southeastern areas of the province. (b) Executive Summary (c) Technical Report Introduction In the recent needs assessment of the Saskatchewan organic industry conducted by Saskatchewan Agriculture and Food, soil fertility and weed management were identified as the two top priorities concerning production research and development. Of specific concern to producers was the decline in soil phosphorous levels occurring in some organic systems, as well as weed control issues. In addition, the desire for producer input and on-farm agronomic research was identified. This project was developed in response to this needs assessment. The overall objective was to identify the state of soil fertility and weed population on organic farms in Saskatchewan and relate these to organic management practices. This project consists of several distinct parts: a questionnaire, soil sampling and analysis and weed surveys. Initially, this project was to begin in the summer of However, this was delayed to the winter of 2001 because of feedback from producers. During this initial telephone contact there was a general reluctance by producers to participate. Overall, it was felt that because of the drought conditions, conditions on their farms were not representative of normal years. A decision was made, in conjunction with Saskatchewan Agriculture and Food staff, to delay the project one year. Specific Objectives: 1. To identify and characterize current farm practices used for soil fertility and weed management by experienced organic farmers in Saskatchewan. 2. To characterize soil fertility and weed populations on organic farms included in this study. 3. To establish a research advisory committee. 4. To identify organic farms suitable for on-farm research projects (see Part II). 2

3 5. To conduct regional workshops on planning and conducting farmer-directed on-farm agronomic research demonstrations. Objective 1: To identify and characterize current farming practices used for soil fertility and weed management by experienced organic farmers in Saskatchewan. Methodology: A questionnaire (Appendix 1) was developed in the summer and fall of 2001 to distribute to organic farmers. The questionnaire was specific to one or two fields on the producer s farm. These fields were to be seeded to wheat (preferably), or another cereal crop in the Spring of Wheat was identified as the test crop so that weed surveys performed on these same fields would be more meaningful, since the host crop affects the types of weeds occurring in a field. The questionnaire was aimed at identifying equipment, organic amendments, seeding and tillage practices and other management practices used by the producer on those specific fields. Lists of potential survey candidates were obtained from cooperating certification bodies including OCIA Chapters 2, 3, 4, 5, 6,and 8. Contacts were made with other certification bodies, who chose not to participate. Sixty-five cooperators were selected based on years of farming experience, soil zone representation, and willingness to participate. Cooperators were required to have at least 2 years of full certification status. Of the 65 cooperators who agreed to participate and were sent surveys, 43 returned completed surveys punctually. Contact was established with all cooperators who failed to return their surveys. In total, 46 growers, with 76 survey fields, participated in this study (Figure 2). Where possible, two wheat fields from each farm were surveyed. If two wheat fields were not available on the cooperator farm, other cereal crops were deemed suitable. All surveying processes (written, soil, and weed populations surveys) were based on these specified fields. Returned surveys were entered in to a database for data summary and analysis. Results and Discussion A total of 46 organic producers with 76 fields were included in this survey. The surveyed producers account for a total of 50,867 certified organic acres in Saskatchewan, with an average farm size of 1,080 acres. Of the total number of acres, 55%, or 27,745 acres, are in annual production. The annual production average per farm was 590 acres. 3

4 Surveyed farms comprised a large, diverse range of commodity production (Table 1). Of the farms surveyed, 97% reported cereal production. Forages (65%), pulses (61%), and oilseed crops (59%) displayed moderately high production percentages. Specialty crop production was reported from 11% of the surveyed farms. Cattle (45%) accounted for the majority of livestock production on surveyed farms, with specialty livestock (mostly sheep and goats) at 19% and hog production at 2%. Producers were asked to identify the three most important management practices utilized on their farms (Table 2). Crop rotation was ranked as the most important management tool. The use of competitive crops was second, followed closely by the use of green manure crops and delayed seeding. Increased seeding rates, spring tillage, fall tillage and post seeding tillage all ranked relatively high. Fifty-seven percent of surveyed producers incorporate green manure crops into their management regimes. Sweet clover was the predominate choice for a green manure plowdown, consisting of 47% of all green manure crops grown over the past five years on surveyed farms (Table 3). Alfalfa, peas, Indianhead lentil, red clover, and chickling vetch were among the other green manure choice crops, ranging from 3 to 20% of production (Table 3). Incorporation dates were generally implemented during the early stages of crop growth ; at pre- and early bloom stages (20% and 48 %, respectively) (Table 4). Eighty-five percent of producers grew green manure crops to improve soil fertility, while 15% reported weed control as the main reason for using green manure crops. This is supported by the fact that all of the green manure crops identified are nitrogen fixing crops. Other crops like fall rye for example have been reported to have allelopathic affects on weeds, but are not in wide usage in the province. The application of soil amendments was a limited practice among producers. Only 15% of surveyed producers had applied amendments over the past five years, while only 11% reported manure application. This number is surprisingly low considering 45% of the surveyed farms raised cattle. However, it may be that the limited amount of manure produced was applied to fields other than the fields included in the survey. Soil amendments other than manure included rock phosphorus, kelp, humic carbon, gypsum, and Penicillium bilaiae (Table 5). The majority of applied manure came from cattle (97%), with sheep accounting for the remaining 3%. Ninety-three percent of applied manure was from on-farm sources, and the average compost period was 8 months. Objective 2: To characterize soil fertility and weed populations on organic farms included in this study. In the spring and summer of 2002, soil tests and weed surveys were conducted throughout the province, respectively. Fields were surveyed in each of the four major agricultural eco-regions of central and southern Saskatchewan; boreal transition, aspen parkland, moist mixed grassland, and mixed grassland corresponding roughly to the grey, black, dark brown and brown soil zones. Eco-regions are classified according to similar climate, soils and natural vegetation (Acton et. al., 1998). The boreal transition ecoregion is the northern limit of agricultural land. It is characterized by grey luvisolic soils in the uplands and 4

5 dark grey chernozemics in the lowlands. It has the most precipitation, the lowest temperatures, and the shortest growing season of the four eco-regions. The aspen parkland is characterized by black chernozemic soils and is warmer and drier than the boreal transition region. Moist mixed grassland is characterized by dark brown chernozemic soils with plains formed by glacial lakes. It is considered a semi-arid region. The mixed grassland eco-region is the warmest and driest area of the province and has the longest growing season. This eco-region is located in the southwest corner; it is characterized by brown chernozemic soils. Materials and Methods Soil sampling Soil samples were collected prior to seeding in the spring of Samples were collected using a hydraulically driven soil probe. A W-pattern was used for sampling across the field (Thomas et al., 1997) (refer to Figure 1). Efforts were made to avoid anomalies in the fields, such as power lines, roads, ditches, sloughs, and so forth. In total, 16 soil samples were collected from each field. Each sample was divided into three depths; 0-15cm, 15-30cm, and 30-45cm. Initial attempts to collect samples to a 60 cm depth were abandoned because the severe soil drying prevented the probes from penetrating to this depth. The 16 samples from each field were bulked according to depth resulting in three samples per field. Insulated storage containers were used to transport samples from the field to the lab. Samples were dried and were analyzed for soil nutrient levels (N P K S), soil moisture, texture, ph, EC, organic matter and bulk density. Soil analyses Macro-nutrient levels of total extractable nitrogen (N), phosphorus (P), potassium (K) and sulfur (S) were measured using standard extraction techniques and colorimetric methods. The modified Kelowna method (Ashwoth and Mrazek, 1995) was used for P and K extraction. An auto-analyser was used for quantification of the P fraction, while the K fraction was analysed by atomic absorption spectrometery. A KCl extraction procedure was performed to obtain the nitrate (NO 3 ), ammonium (NH 4 ) and sulphate (SO - 4 ) extractable fractions. These fractions were also analyzed colorimetrically with an auto analyser (Biederbeck et. al, 1996). Tests for moisture content, bulk density, ph, electrical conductivity, texture, and organic matter followed the Soil Science Society of America Methods of Soil Analysis suggested protocol. The gravimetric method was used to determine moisture content (Gardner, 1986). Soil mass was measured prior to and after a 24-hour drying period in a 105 o C oven. Three sub-samples were analyzed. Bulk density also required the mass of oven-dried soil of a known volume to calculate soil density. Three soil cores of known volume were collected from each field and were analysed separately. ph and electrical conductivity were determined using the saturated paste method (Rhoades, 1996). Because soil saturation levels vary greatly with texture, the least amount of water added to reach saturation allows for a more accurate reading of the solutes in the soil (Rhoades, 1996). Because of the wide array of soil samples collected, the saturated paste method was chosen, as it more accurately 5

6 represents field capacity than the 1:1 or 1:2 solution methods. ph readings were taken after the soil/water pastes had soaked for 24 hours. The paste samples were then vacuum filtered and the extractant used to measure electrical conductivity with a conductance meter at room temperature (25 C). Soil texture was determined by the use of a hydrometer, which is dependent on Stoke s Law (the principle of sedimentation) in order to determine the sand, silt, and clay fractions. Proportions of sand, silt and clay are then applied to the Canadian classification system referred to as the texture triangle (Gee and Bauder, 1986). Organic matter was determined using a combustion method. Since most organic C is present in the soil organic matter and carbon is known to be 48 to 58% of the total weight of organic matter, the determined value of the incinerated organic carbon is converted to organic matter by multiplying organic carbon by an estimated constant (Nelson and Sommers, 1982). Soil samples were ball ground in order to ensure a uniform sample that burnt evenly and quickly at 804 o C in a muffle furnace. Weed surveying Weed surveying commenced in mid July and was completed by early August. Surveying protocol from Thomas et al. (1997) was used for weed population counts (refer to Figure 1). One-quarter meter quadrats were implemented as the counting area. In total 20 quadrats were counted in a W-pattern across each field. Efforts were made to avoid anomalies in the fields, such as power lines, roads, ditches, sloughs, and so forth. In order to ensure that only weeds that would be competitive with the standing crop were included, only weeds that were larger than the first true leaf stage were identified and counted. Sampling later in the growing season also ensured that any management practices implemented earlier in the year had time to manifest an effect on weed populations. Protocol for data analysis was based on Thomas (1985). Relative abundance is obtained by the summation of three descriptive components: density, frequency, and uniformity. Density measures the number of a species counted in each square meter expressed as a percent of the total number of a single weed species present. The 20 sampling sites in each field are averaged to obtain a density value for each species present. The maximum value for density is 100%. Frequency is the number of fields in which a weed species occurred, expressed as a percentage of the total fields surveyed. The maximum frequency obtainable is 100%. Uniformity is a measure of the number of quadrats where a species occurred expressed as a percentage of the total number of quadrats in the survey (20 quadrats x 76 fields). It also has a maximum value of 100%. These three measurements when summed provide a measure of relative abundance. The maximum value obtainable for relative abundance is 300 (Table 4). The measure of relative abundance is without units but allows for a comparison tool between unrelated species. The relative abundance measure takes into account whether or not a species is present on a field, and if so how patchy its distribution is, as well as the total number of individual plants present for each species. 6

7 Results and Discussion: Soil Survey Soil survey results are grouped according to eco-region classifications. The lowest mean levels of N, P, K and S in the top 15 cm were reported in the boreal transition eco-region (Table 6). The moist mixed grassland eco-region had the highest mean values for N, P and K; while the aspen parkland eco-region had the highest S value. Critical nutrient levels (Table 7) compare the general nutrient condition of the surveyed fields. This table gives generalized values; these values will differ depending on the nutrient demand of the planted crop. The mean soil N content for all eco-regions reported deficient levels. Values as low as 4 lb/acre were found. However, values in the optimal range (>100 lb/acre) were not uncommon. The fact that these maximum values were obtained suggests that nitrogen can be managed to optimal levels in an organic systems. Unlike nitrogen levels where some fields were deficient and others optimal, available phosphorus levels were extremely low in all fields tested (Table 7). Maximum values did not report above the deficient level. This suggests that avalilable phosphorus is difficult to maintain at optimal levels under an organic farm management. A Manitoba study on 170 fields on 14 organic farms over six years found similar results. Entz, et al. (2001) reported that phosphorus levels were low on all field and were particularly low on fields that were managed organically for 30 years or more. Unlike nitrogen, plants are unable to fix phosphorus into useable forms. All phosphorus for plant growth is supplied by the soil. Without supplying phosphorus back to the soil through the addition of organic fertilizers, the soil will eventually be unable to supply phosphorus to sustain crop growth. Although many soils do contain relatively good stores of phosphorus, simply making these stores plant available is not the answer. With each harvest of a crop, phosphorus is removed from the system. A priority for organic systems must be to identify acceptable amendments for replacing phosphorus to the soil. Livestock manures are good candidates. Saskatchewan soils naturally contain high levels of potassium, particularly in southern and central regions of the province. Reported potassium values correspond to these levels as all are in the optimal range. The boreal transition eco-region was the only region with a minimum value in the deficient range (Table 7). This however, was an usual situation. Potassium is unlikely to present a problem for plant growth in all but possibly the boreal transition. Soil sulphur levels vary greatly in all eco-regions (Table 7). Except for the boreal transition region, most of the sulphur values fell in the marginal or higher category. Values in the boreal transition tend to report deficiency. In each of the other eco-regions, maximum values fell in the excess category for sulphur. Fields reporting very high sulphur levels were associated with slightly saline fields. The majority of naturally occurring salts in Saskatchewan are the result of sulphate salts (MgSO4, CaSO4, NaSO4), rather than chlorides. However, high salinity was not a problem in any of the sampled fields as measured by electrical conductivity (EC) (Table 8). Values exceeding 4.0mS/cm are classified as moderately saline. None of the fields reported EC values as high as 4 ms/cm. 7

8 The mean ph values for all soils were in the neutral range of 7.0 (Table 8). Some acidic soils were identified in each of the eco-regions. The mixed grassland and aspen parkland each had ph values as low as 5.5. The largest affect ph has on soil characteristics is on the availability of nutrients. Phosphorus for example is more available in acidic soils than neutral or alkaline soils. Micronutrient availability is greatly affected by ph, some micronutrients like, copper, iron and zinc are more available in acidic conditions and can reach toxic amounts. Other micronutrients like boron, become less available in acidic conditions and can be a risk of deficiency in these soils. Not unexpectedly, the highest mean organic matter values exist in the aspen parkland region, corresponding to the black soil zone. Soil zones are classified according to predominant soil color, which reflects the amount of organic matter. The moist mixed grassland (dark brown), boreal transition (grey), and the mixed grassland (brown) values were respectively lower. Any management practice that minimizes the removal of organic matter from the system will increase soil organic matter and will ultimately have positive effects on productivity. Decaying organic matter not only supplies nutrients, it improves water holding capacity, reduces erosion by wind and water and improves the overall structure of the soil. Weed Survey A total of 67 weed species were identified from the 76 surveyed fields. Relative abundance values quantified the weed species that are most abundant in certain defined boundaries. Provincially, the 15 most abundant species ranged from 5% to 70% relative abundance in the four different eco-regions (Table 9). Green foxtail (Setaria virids (L.) Beauv.) was the most abundant weed species on sampled organic farms in Saskatchewan. Wild mustard (Sinapis arvensis L.) was second, followed by lamb s quarters (Chenopodium album L.) and wild oats (Avena fatua L.). Wild buckwheat (Polygonum convolvulus L.) and stinkweed (Thlaspi arvense L.) were fifth and sixth respectively. Green foxtail (Setaria virids (L.) Beauv.) was highest in all eco-regions except for the most northern, boreal transition eco-region, where it was second to lamb s quarters (Chenopodium album L.) (Table 9). Wild mustard (Sinapis arvensis L.) was ranked second in most regions, with the exception of the boreal transition where it was ranked third. The range of relative abundance in wild mustard between all four eco-regions was minimal, from 35% to 41%. This range for most other weed species is greater, which suggests preferential growth regions. It also suggests that wild mustard has a greater adaptive ability to persist in differing eco-regions. Wild buckwheat (Polygonum convolvulus L.) and wild oats (Avena fatua L.) also have a relative abundance range similar to that of wild mustard, but are less abundant, ranging from and respectively. The relative abundance value for lamb s quarters in the boreal transition eco-region is more than twice any of the other regions. This can be contributed to differences in plant densities, which were much higher in the boreal transition (23%) than in the mixed grassland (3%), aspen parkland (5%) or moist mixed grassland (14%). 8

9 Stinkweed (Thlaspi arvense L.) was twice as abundant in the mixed grassland compared to all other eco-regions. Canada thistle (Cirsium arvense (L.) Scop.) was most abundant in the aspen parkland. Surveyed fields show a high abundance of annual broadleaved weeds, such as, wild mustard, wild buckwheat, lamb s quarters and stinkweed. This contrasts conventional weed survey results in Saskatchewan in , 1986 and The summarized data shows a 17% decrease in annual broadleaved weeds (Thomas et. al., 1996). This decrease may be attributed to a shift in conventional agriculture in Saskatchewan. Over the past 20 years, the frequency of reduced tillage, direct seeding, continuous cropping, and crop diversity has increased (Thomas, 1996). Since most annual broad-leaved weeds are easily controlled with herbicides and mangament practices, this type of system is likely to have contributed to the reduction of annual broadleaved weed species. The morphology of a broad-leaved species is also more easily controlled with herbicides than grassy weed species in conventional systems. Objective 3: To establish a research advisory committee. A research advisory committee has been established with representation from various sectors of organic agriculture. Grower representation consists of four organic farmers located throughout the province. Table 1 presents a detailed member list. This committee was established to provide growers the opportunity to input, direct, and express current issues to be addressed in field research experiments. The committee is to act in an advisory capacity to assist in identifying possible treatments for the companion on-farm research experiments. In this second project small plot experiments have been established at three sites on organic land. The committee also discussed specific treatments to be established at the sites. Objective 4: To identify organic farms suitable for on-farm research projects. Three sites have been identified for the on-farm research projects in Part II and the first year of research has been conducted. These sites include the Agriculture and AgriFood Canada Research Station at Scott (dark brown soil zone), the Loiselle Organic Farm near Vonda (thin black soil zone), and the Richman Homestead Farm near Elbow (brown soil zone). The sites at Vonda and Elbow have been certified organic for over ten years. Both producers hold certification under OCIA certification bodies, chapters 2 and 4, respectively. Details of the on-farm research projects will not be reported on here. Objective 5: To conduct regional workshops on planning and conducting farmer-directed on-farm agronomic research demonstrations. Two Organic On-Farm Research Workshops were organized and held in Melfort (January 29, 2002) and in Gull Lake (February 7, 2002). These workshops focused on producer input into issues that are important to them, and planning and conducting on-farm agronomic trials. The workshops were organized 9

10 with the help of SAF representatives from the area (Leroy Bader, Melfort Workshop; Jay Protz, Pat Gerwing and Darryl Tumbach Gull Lake Workshop). Each workshop was attended by approximately 25 organic producers from the surrounding area. Discussion groups were organized to obtain information from producers regarding pertinent topics in organic production. Discussion topics included crop rotations, the use of green manure crops, weed management procedures, the use of different varieties, soil amendments, and inoculants. Detailed information on how to conduct on-farm research was presented in the afternoon. A Research Guide was provided to all in attendance (Appendix 2). Feedback from the workshops indicated that they were very well received. Producer input was very positive and enthusiastic. Conclusions 10

11 Figure 1. Field sampling pattern implemented in soil sampling and weed population surveys. 100 paces paces Figure 2. Location of Surveyed Land. 11

12 Table 10. Research Advisory Committee Members Name Title Association Location Blaine Reckseidler Cereals and Organic Crops Specialist Saskatchewan Agriculture and Food Saskatoon Denis Brodner Organic Farmer OCIA 4 Cupar Dr. Diane Knight Research Scientist Dept. of Soil Science, U of S Saskatoon Eric Johnson Soils and Crops Agrologist Agriculture and AgriFood Canada Scott Ian Cuchon Organic Farmer OCIA 4 Oxbow Kevin Beach Organic Farmer OCIA 8 Ernfold Marc Loiselle Organic Farmer OCIA 2 Vonda Dr. Steve Shirtliffe Assistant Professor Dept. of Plant Sciences, U of S Saskatoon Dr. Stuart Brandt Soils and Crops Agronomist Agriculture and AgriFood Canada Scott Table 1. Commodity production on surveyed organic farms. Values are expressed as a percentage of surveyed farms that produce each commodity. Farm Production Commodities (%) Cereals 97 Forages 64 Oilseeds 59 Cattle 45 Pulses 61 Hogs 2 Other crops 11 Other livestock 19 Table 2. Priority of Management Practices. Priority (%) Weighed Management Practice #1 #2 #3 sum 1 Rotate crops Grow competitive crops Grow green manure crops Delayed seeding Increase seeding rate Use spring tillage Summerfallow Use post seeding tillage Use fall tillage Lunar phase Cultivation Vary seeding date Mow weed patches Narrow row spacing Inter-row cultivation Weed plowdown Deep tillage in spring & fall Fall/spring grazing Weed clipping weighed sum = (%first priority x 3) + (%second priority x 2) + (%third priority x 1) 12

13 Table 3. Type of green manure crops used by surveyed producers. Values are expressed as a percentage of surveyed farms that produced grren manure crops over the past five years. Green Manure Crop (%) Sweet clover 47 Alfalfa 19 Peas 11 Indianhead Lentil 10 Red Clover 7 AC Greenfix 3 Other 3 Table 4. Incorporation stages of green manure crops. Values are expressed as a percentage of surveyed farms that produced green manure crops over the past five years. Incorporation Stage (%) Early bloom 48 Post-bloom 22 Pre-bloom 20 Late bloom 10 Table 5. Soil amendments usage. Values are expressed as a percentage of surveyed farms that have applied soil amendments over the past five years. Occurrence Soil Amendments (%) Rock phosphorus 42 kelp 17 gypsum 17 humic carbon 17 P. billai 8 13

14 Table 6. Mean, Minimum and Minimum Soil Nutrient Levels Displayed in Pounds per Acre From the Four Eco-Regions in South/Central Saskatchewan for Nitrogen (N), Phosphorus (P), Potassium (K) and Sulphur (S) for a 0 cm to15 cm sampling depth. Eco-Region Measure N P K S Aspen Parkland Mean Maximum Minimum Moist Mixed Grassland Mean Maximum Minimum Mixed Grassland Mean Maximum Minimum Boreal Transition Mean Maximum Minimum Table 7. Generalized critical limits from Northwest labs (1994). Critical Levels N P K S Deficient < 60 < 30 < 160 < 8 Marginal Optimal Excess > 220 > 120 > 1000 > 80 (Norwest Labs Agricultural Soils Reference Chart. Norwest Labs: Edmonton, Alta.) Table 8. Mean, Minimum and Minimum Soil Prosperities Displayed From the Four Eco-Regions in South/Central Saskatchewan for ph, Electrical Conductivity (EC) and Organic Matter for the 0 cm to 15 cm depth. Eco-Region Measure ph EC (ms/cm) Organic Matter (%) Aspen Parkland Mean Maximum Minimum Moist Mixed Grassland Mean Maximum Minimum Mixed Grassland Mean Maximum Minimum Boreal Transition Mean Maximum Minimum

15 Table 9. Relative Abundance Values 1 and Ranking (in Parentheses) of the Most Abundant Weed Species are Identified for All of Saskatchewan and the Four Major Agricultural Eco-Regions of Saskatchewan. Relative Abundance 1 and Ranking in Parentheses Weed Species Green foxtail Setaria virids (L.) Beauv. Wild mustard Sinapis arvensis L. Lamb s quarters Chenopodium album L. Wild oats Avena sativa L. Wild buckwheat Polygonum convolvulus L. Stinkweed Thlaspi arvense L. Canada thistle Cirsium arvense (L.) Scop. Redroot pigweed Amaranthus retroflexus L. Volunteer Alfalfa Medicago sativa L. Russian thistle Salsola pestifer A. Nels. Dandelion Taraxacum officinale Weber Flixweed Descurainia sophia (L.) Webb Blue bur Lappula echinata Gilib. Perennial sow thistle Sonchus arvensis L. Black medic (Medicago lupulina L. Saskatchewan Mixed Grassland Eco-regions of Saskatchewan Moist Mixed Grassland Aspen Parkland Boreal Transition 60 (1) 51 (1) 58 (1) 70 (1) 41 (2) 41 (2) 40 (2) 41 (2) 40 (2) 35 (3) 35 (3) 19 (6) 31 (3) 28 (3) 51 (1) 27 (4) 26 (4) 19 (5) 27 (4) 29 (4) 24 (5) 20 (5) 21 (4) 19 (5) 25 (5) 19 (6) 37 (3) 16 (6) 9 (8) 16 (6) 11 (7) 8 (10) 7 (10) 14 (6) 9 (8) 8 (8) 14 (7) 9 (9) 6 (11) 2 (-) 8 (9) 0 (-) 10 (8) 7 (10) 11 (7) 8 (10) 8 (10) 16 (7) 5 (14) 0 (-) 6 (11) 6 (13) 5 (18) 4 (17) 7 (10) 6 (12) 13 (8) 5 (15) 3 (18) 2 (-) 6 (13) 3 (14) 5 (17) 10 (7) 3 (16) 5 (14) 7 (12) 4 (19) 5 (13) 3 (17) 5 (15) 8 (10) 5 (16) 3 (20) 1 (-) Species 16 to 20 for the Saskatchewan are Cow Cockle (Saponaria vaccaria L.), Quackgrass (Agropyron repens), Prostrate Knotweed (Polygonum aviculare L.), Kochia (Kochia scoparia (L.) Schrad.), and Smart Weed species (Polygonum spp.) respectively. 1 Relative abundance is a unit-less measure. The maximum value of relative abundance is would occur if the three components have a value of a 100%. 100% occurs in density if all weeds present are of a single species, 100% uniformity occurs if every sampling site had that species present and 100% frequency occurs if every field had the species present. 15

16 References Cited Acton, D.F., G.A. Padbury, and C.T. Stushnoff The ecoregions of Saskatchewan. Hignell Printing Limited: Winnipeg, MB. Ashworth, John and Den Mrazek Modified Kelowna test for available phosphorus and potassium in soil. Communications in Soil Science and Plant Analysis 26 (5&6), Biederbeck, V.O., O.T. Bouman, C.A. Campbell, L.D. Bailey and G.E. Winkleman Nitrogen benefits from four green-manure legumes in dryland cropping systems. Canadian Journal of Plant Science 76: Biederbeck, V.O., and J. Looman Growth of annual legumes for soil conservation under severe drought conditions. Soils and Crops, University of Saskatchewan, Saskatoon Entz, M.H., R. Guilford, and R. Gulden. Crop yield and soil nutrient status on 14 organic farms in the eastern portion of the northern Great Plains. Canadian Journal of Plant Science. 81: Gardner, Walter H Water Content. In Methods of Soil Analysis Part 1: Physical and Mineralogical Methods. 2 nd Edition. Ed. A. Klute. Soil Science Society of America, Madison, WI Gee, G.W. and Bauder Particle-size Analysis. In Methods of Soil Analysis Part 1: Physical and Mineralogical Methods. 2 nd Edition. Ed. A. Klute. Soil Science Society of America, Madison, WI Macey, Anne Statistics 2000: Organic farming in Canada. EcoFarm & Garden: Nelson, D.W. and L.E.Sommers Total carbon, organic carbon, and organic matter. In Methods of Soil Analysis Part 1: Physical and Mineralogical Methods. 2 nd Edition. Ed. A.L. Page. Soil Science Society of America, Madison, WI P.Qian and J.J. Schoenau Fractionation of P in soil as influenced by a single addition of liquid swine manure. Canadian Journal of Soil Science 80: P.Qian, J.J. Schoenau, and W.Z. Huang Use of ion exchange membranes in routine soil testing. Communications in Soil Science and Plant Analysis 23: Rhoades, J.D Salinity: electrical conductivity and total dissolved solids. In Methods of Soil Analysis Part 3 Chemical Methods 3 rd Edition. Ed. D. L. Sparks. Soil Science Society of America, Madison, WI Saskatchewan Agriculture and Food Saskatchewan s Organic Industry. Regina, Saskatchewan. (Verified 27 February, 2003). Thomas, A. Gordon Weed survey system used in Saskatchewan for cereal and oilseed crops. Weed Science 33: Thomas, A.G., R.F. Wise, B.L. Frick and L.T. Juras Saskatchewan weed survey: cereal, oilseed and pulse crops Agriculture and Agri-Food Canada: Saskatoon, Saskatchewan. 419 p. Thomas, A. Gordon, Brenda L Frick, David Kelner, and Robin F. Wise Manitoba weed survey: Comparing zero and conventional tillage crop production systems Weed Survey Series Publication Manitoba Agriculture, Carman. 130 pp. 16

17 (d) Personnel: K.Hunter administrative 2 months R.German technical (Plant Sciences) 12 months K. Smith technical (Soil Sciences) 4 months R. Buhler graduate student 12 month M. Braun summer student 4 months (e) Equipment: none to report (f) Project Developed Materials: Appendix 1 : Organic On-Farm Management Questionnaire Appendix 2: Research Guide for Farmer Managed Trials on Organic Farms (g) Project Photos: none to report (h) Acknowledgements: SAF has been identified as the funding agency in all meetings, workshops and interviews that have been performed. (i) Expense Statement: provided by financial office, U. of S. 17

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